This taxon is usually included in M. rufocanus (G.M. Allen, 1940; Ellerman and Morrison-Scott 1951; Gromov and Polyakov 1977; Hinton 1926; also see references in Kaneko 1990) but it was treated as a separate species by Corbet (1978). In a study of red-backed voles from Russia, northeastern China, and Korea, Kaneko (1990) thoroughly documented morphological distinctions between M. rufocanus and M. regulus, considering the latter to be a Korean endemic and suggesting that "the true geographical demarcation line between the two species lies on the western and southern boundary of the Kaima Plateau, North Korea." Kaneko also discovered that adult and old regulus lack molar roots, a key character for separating Myodes from Eothenomys, and so transferred it to Eothenomys.

Subsequent mitochondrial and nuclear ribosomal DNA analyses conclusively demonstrate that M. regulus is distinct but phylogenetically close to M. rufocanus, not typical Eothenomys (Suzuki et al. 1999). Wakana et al. (1996) noted that the "absence of rooting of the molars in the Korean vole … is a characteristic that may have developed within a short period of evolutional time in the Korean population." The G-banding pattern of regulus is "essentially identical" to that of M. rufocanus, both differing from M. glareolus, but Y-chromosome morphology implicates closer relationship between M. regulus and M. smithii (Iwasa et al., 1999), a Japanese vole also having unrooted molars. Iwasa et al. (1999) stated that phylogenetic affinities among rufocanus, regulus, and smithii</i. "are extremely complicated." To this complicated mix must be added M. shanseius (also rootless), which is so morphologically similar to M. regulus that the same specimens have been variously identified as one or the other. They differ only in length of tail, interorbital breadth, and M3 occlusal patterns; as currently known, their distributions are allopatric, perhaps separated by the Liao He River in Liaoning Province (Kaneko, 1992). The genetic integrity of M. regulus relative to M. shanseius similarly warrants additional study.

Justification:
Listed as Least Concern in view of its wide distribution, tolerance of a broad range of habitats, presumed large population, and because it is unlikely to be declining fast enough to qualify for listing in a more threatened category.

This vole occupies a fairly wide variety of habitats, but seemingly avoids extensive forests (Won, 1967). Specimens of this species have been collected from scrub-covered hillsides, talus slopes, forested areas, abandoned paddy fields, the edge of the forest, old logs, tree stumps, and often near the bank of streams (Won and Smith, 1999; Allen and Andrews, 1913; Jones and Johnson, 1965; Won, 1967). It can probably adapt to some anthropogenic habitats.